Try NOP-ing instead of inverting.
Thanks, I´ll give it a try.
I´ll also take a longer look at this. I can neither actually sure say that I found all what I need, else that I´m on the right way, but the fact that the checksum-error won´t occur make me believe that this could be the right direction.
chksum check can be disabled in flash. this works to remove rom errors when editing data outside the normal chk`d area, possible will fix your chksum issue as well.
Okay, thats what I tried, but my knowledge is really limited actually about things like this, maybe you can give me a hint?